!!! goto !!!

goto.rb

require 'continuation'

module Kernel
  def labels
    $labels ||= {}
  end

  def label(name)
    callcc { |c| labels[name] = c }
  end

  def goto(name)
    labels[name].call
  end
end

i = 0

label 10
puts i += 1
goto 10 if i < 10

label :nyan
puts i -= 1
goto :nyan if i > 0